1. Field of the Invention
The present invention relates to a torque fluctuation absorber.
2. Description of the Related Art
A damper disc provided between an output shaft of an engine and an input shaft of a transmission or the like, a torque fluctuation absorber with a torque limiter, and so on are known.
For example, Japanese Patent Application Publication No. 61-41019 (JP-A-61-41019) describes a damper disc having an annular side-plate having an input portion along its outer periphery; a flange; and spring mechanisms received in window holes defined by the side plate and the flange.
Japanese Patent Application Publication No. 2002-39210 (JP-A-2002-39210) describes a torque fluctuation absorber having a torque limiter portion, which includes: a driven plate spline-fitted to a driven side input shaft; drive plates disposed on both sides of the driven plate; and spring dampers received in window holes defined by the driven plate and the drive plates.
However, the damper disc described in JP-A-61-41019 has a limitation on the size of the window holes to ensure that the side plate and the flange have sufficient rigidity. Thus, the size of the springs which can be received in the window holes is limited.
The torque fluctuation absorber described in JP-A-2002-39210 also has a limitation on the size of the window holes to ensure that drive plates and driven plate have sufficient rigidity, and therefore the size of the spring dampers which can be received in the window holes is limited.
As described above, the damper disc and the torque fluctuation absorber have a limitation on the size of the spring dampers or the like which can be used therein. Therefore, when the power from a power source, such as an engine, is transmitted to an output portion, such as a transmission, there arises a problem that the torque fluctuations cannot be sufficiently absorbed, causing vibration to the entire transmission.
On the other hand, there is a tendency that the space that can be allocated for a torque fluctuation absorber in an engine compartment is decreasing, therefore the demand for reduction in size of torque fluctuation absorbers is increasing.